Manual ventilation or resuscitation is performed on an individual when they are unable to breathe independently. Typically, this occurs when an individual is transported from one section of a hospital to another section such as an emergency room and an intensive care unit, or in an ambulance. Manual resuscitation also occurs during cardiopulmonary resuscitation (CPR), which is a standard technique applied to victims of cardiopulmonary arrest with the goal to re-establish normal cardiac and respiratory function.
Ventilation from a manual resuscitation device is currently provided by a self-filling elastomeric enclosure or bag. This bag is compressible by hand, a face-fitting mask (or intubation tube) in fluid communication with an outlet passage of the bag, and a one-way valve between the mask and bag to permit only fluid passage from the bag to the mask. The bag also has an inlet passage, typically with one opening for air and another, usually smaller opening for receiving oxygen. By squeezing the bag with their hand(s), a clinician delivers air or oxygen to an individual, and then releases the bag to permit it to expand to full size and thereby draw air or oxygen through the inlet passage.
The amount of air received by the lungs of the individual corresponds to the volume of the bag. A larger bag provides a greater maximum volume of air to be pumped into the individual. Children and infants typically have smaller lungs than an adult, and therefore conventional manual resuscitation devices are provided in different sizes; e.g., infant, child and adult. Each size provides a different maximum volumetric output of air. Depending on factors such as physical condition, body size, age, sex, etc., each individual may require a specific volume of air (tidal volume), and frequency, and minute ventilation.
Unfortunately, current manual ventilation or resuscitation devices are not suitable for the desired monitoring and control of tidal volume delivery. For instance, the collapsible bag portion of the resuscitation device allows the user to merely “feel” the amount of air they are providing to the individual. This provides them merely a very rough estimate of the volume of air they are providing and a tactile feel for when the lungs are non-compliant, i.e. are being pressurized. Although self-filling respiration (resuscitation) enclosures or bags can be selected on the basis of known maximum volumes, the volume actually delivered can vary substantially among several operators, dependent upon factors such as hand size, number of hands used, technique, enthusiasm and fatigue. These variations have been shown to be as much as 60 percent of the optimal tidal volume. Frequency can also vary between users, resulting in potential underventilation or overventilation.
Accordingly, what is needed is a single manual ventilation or resuscitation device that can be used on any patient, regardless of individual factors such as physical condition, body/lung size, age and sex.